sizeof(struct json_object_iterator)/sizeof(void *)=1
key: string_of_digits
pre change:  "123"
post change: "switched"
key: regular_number
pre change:  222
post change: "switched"
key: decimal_number
pre change:  99.55
post change: "switched"
key: boolean_true
pre change:  true
post change: "switched"
key: boolean_false
pre change:  false
post change: "switched"
key: big_number
pre change:  2147483649
post change: "switched"
key: a_null
pre change:  null
post change: "switched"
key: an_object
pre change:  { "foo": "bar" }
post change: { "foo": "change foo", "newkey": "new value" }